Needled fabrics and process for making them



April 14, 1970 .J.S'ANDERS- 3,506,529

NEEDLED FABRICS AND PROCESS FOR MAKING THEM Filed A 2, 1965 1.

l2 /a 22 M,

\ 6 20 I28 /6 mumlllmmlmmmmln 3 INVENTOR ATTORNEYS United States Patent 3,506,529 NEEDLED FABRICS AND PROCESS FOR MAKING THEM Arthur Joseph Sanders, Llanyravon, England, assignor to British Nylon Spinner Limited, Pontypool, England Filed Aug. 2, 1965, Ser. No. 476,677 Claims priority, application Great Britain, Aug. 19, 1964, 33,872/ 64 Int. Cl. D04h 11/08 US. Cl. 161-67 Claims ABSTRACT OF THE DISCLOSURE A fabric suitable for upholstery or cold-weather ap parel is made by interposing a layer of flexible foam material between two fibrous layers, needle punching at least one side of the laminate, then bonding. The fibers which project beyond the outer face of the fibrous layer are subject to a crimping treatment, forming mushroom-shaped protuberances which press against the outer face. Preferably the fibres, particularly the needle-punched fibres, are composite fibres which are potentially crimpable and which include a potentially crimpable component so that the bonding step may be effected by activating the crimp and the adhesive component.

The present invention is concerned with a new fabric containing a layer of a flexible foam material, and a process for manufacturing the fabric.

The new fabric material according to the invention comprises a layer of a flexible foam material sandwiched between, and secured to two fibrous layers, each consisting of one or more fibrous webs.

In a highly advantageous fabric provided by this invention, the two fibrous layers are held against the layer of the flexible foam material by fibres disposed in the thickness direction of the fabric and traversing the flexible foam layer.

The invention also provides a process for manufacturing the fabric which comprises interposing a layer of a flexible foam material between two fibrous layers each formed of one or more fibrous webs, and securing the foam material to the two fibrous layers. The foam material may be secured to the two fibrous layers in a variety of ways. Preferably however, in the interests of imparting to the fabric a good dimensional stability and resistance to delamination, the foam layer is secured to the two fibrous layers by needle-punching the sandwich structure, from one or both sides thereof, in a needle loom. As a result of the needle punching which may be achieved by any conventional single or, where appropriate, double-bed, needle loom, fibres from a fibrous layer are carried through the foam material and into the opposite fibrous layer. Either, or both of the surfaces of the fabric can be provided with a pile by suitably arranging that the depth of needling is adequate not only to carry fibres into the opposite fibrous layer but through the layer so that they project beyond it as fibre tufts. These fibre tufts, which may be present on one or both of the surface of the fabric, form a pilouslike surface and endow the fabric with an interesting appearance and a pleasant, textile-like handle.

In those fabrics wherein the foam layer is secured to the two fibrous layers by the needle-punching of fibres from at least one of the fibrous layers through the foam, a more effective keying of the foam layer and consequently an enhanced dimensional stability and resistance to delamination, can be attained by including in either or both of the fibrous layers, a proportion of retractable fibres, or constructing either or both of the layers, entirely of such fibres, and subjecting the needle-punched structure 3,506,529 Patented Apr. 14, 1970 ice to a treatment to retract those fibres. The term retraction is used herein in relation either to a reduction in length of the fibre arising from shrinkage, or from a distortion of the fibre into an irregular shape by the development of crimp, or both.

Fabrics in which the properties of dimensional stability, tensile strength, and resistance to delamination are developed to a maximum extent compatible with the retention of a reasonable drape, flexibility and resiliency are provided in a further modification of the invention, wherein fibres present in the fabric are bonded to one another. Preferably the bonding together of fibre in the fabric is effected by inter-fibre adhesion. When composite fibres, that is fibres which contain two or more fibre-forming polymeric components arranged in adherent relationship along the length of the fibre, are present in either or both of the fibrous layers as the retractable fibres, then interfibre adhesion may conveniently be affected by activating potentially adhesive component in the composite fibres.

The term fibre includes continuous filaments wherever the context does not indicate that only short staple fibres are meant.

The initial fibrous webs may be made of any kind of fibre, natural or synthetic, which are suitable for use in the manufacture of fabrics. As example of such fibres there may be mentioned:

Cotton.

Silk.

Wool.

Cellulose fibres including those derived from cellulose esters such as cellulose acetate.

Polyamide fibres such as polyhexamethylene adipamide fibres and polycaproamide fibres.

Polyester fibres such as Terylene.

Hydrocarbon fibres such as polyethylene and polypropylene and acrylic fibres such as Dynel and Orlon.

The words Terylene, Dynel and Orlon" are registered trademarks.

The fibrous web may be made by the air deposition of fibres, by garnetting processes, by carding fibres followed by the cross-laying of the carded webs, by fluid papermaking techniques and indeed by any method whereby a web of loosely associated fibres may be formed.

Continuous filament webs may conveniently be prepared by drawing oif the filaments directly from a spinning unit, or they may be formed from a package or other storage device for yarn already spun. Continuous filament yarn webs, that is to say, webs in which the filaments are present as multifilaments, may conveniently be prepared in a process wherein freshly spun filaments comprising one or more polymer components are subjected to the action of a high velocity turbulent fluid jet which attenuates and orients the filaments and intermingles them to form a twistless yarn, which yarn is forwarded by the fluid jet and deposited on a recurring surface in a random loopy manner.

To a certain extent the method employed is dependent upon the length of the fibres being processed.

In those fabrics wherein it is desired to reinforce the effect of the needle punching in securing the foam layer in position, by the retraction of fibres present in the fabric, it is necessary that there be present therein a proportion, generally not less than 20 percent, distributed in either or both of the fibrous layers, of fibre having the ability to retract when treated in an appropriate manner.

Practically all artificial fibre may be made in such a way that they process the ability to retract when appropriately treated. Thus, fibres may possess the ability because of physical asymmetry, non-homogeneity of composition, or different stresses imparted to the fibre during its manufacture, or developed subsequently by an appropriate physical or chemical treatment. Whether the latent retractibility be inherent or induced, it can be developed by a heat or chemical treatment (for instance by an organic swelling agent for the particular fibre) and its development is accompanied by a shrinkage of the fibre or its distortion into an irregular shape by crimping or both. Whatever form it takes retraction of the fibre more effectively secures the foam layer to the two outer fibrous layers and consequently enhances the dimensional stability, tensile strength and resistance to delamination of the fabric. Examples of suitable retractable fibres include polyethylene, polypropylene, polyacrylonitrile, polyvinyl chloride polyamide and polyester fibres.

Especially desirable results in the manufacture of the fabrics of the invention have been obtained with composite fibres, i.e. fibres which contain two or more fibre forming polymeric components arranged in an adherent relationship along the length of the fibres. Particularly suitable fibres are those in which one of the components is located in the fibre so as to form at least a portion of its peripheral surface, and is capable of being activated i.e. made adhesive, under conditions not sensibly affecting the other component or components. The use of such provides for the further reinforcement, if desired, of the tensile strength and dimensional stability of the fabric, through the activation of the potentially adhesive component which then serves as a bonding agent to adhesively bond contiguous fibres in the fabric.

The activation of the potentially adhesive component with the in situ development of a bonding agent is preferably effected in the same treatment as that in which the composite fibres are crimped.

Activation, is normally accomplished without destruction of the composite fibres, for the activated component is maintained in association with the other component or components of the fibre and does not migrate throughout the fibrous web.

Examples of composite fibres containing such a potentially adhesive component are polyhexamethylene adipamide-polyepsilon caprolactam (Nylon 66/6) fibres in which polyepsilon caprolactam is the potentially adhesive component, polyhexamethylene adipamide-polyomegaaminoundecanoic acid (Nylon 66/11) fibres in which the polyomegaaminoundecanoic acid is the potentially adhesive component, and polyhexamethylene adipamide/ polyhexamethylene adipamide polyepsilon caprolactam copolymer fibres in which the copolymer component is the potentially adhesive component. In each case the potentially adhesive component may be activated by a heat treatment. Composite fibres other than those based on the polyamide system may also be used. Thus composite fibres formed, for example from polymers based on polyesteramides, polyesters polyhydrocarbons and polyurethanes may be suitable.

The fibrous layer or layers of which the fibrous assembly is composed and which itself consists of one or more of such fibrous webs, generally has a weight in excess of 0.4 ounce per square yard and preferably not less than 1 ounce per square yard, so that the weight of the initial fibrous web is adjusted in relation to the desired weight for the fibrous layers and the number of such webs utilised in the making thereof. Conveniently, the weight of the initial fibrous web varies from about 1 to ounces per square yard.

The foam material comprising the central layer of the novel fabrics may be a natural or synthetic rubber or a foamed plastic material.

Foamed plastic materials sometimes referred to as expandable plastics, are characterised by a cellular structure which provides them with a good flexibility and resiliency.

A fuller account of plastic foams including details of their manufacture and properties is to be found at pages 4 341-3 64 in Modern Plastics Encyclopedia for 1964 published in New York in September 1963 by Plastics Catalogue Corporation.

Among the plastic foams which in sheet form may constitute the central layer, mention may be made of polyurethanes, polyolefines, polystyrene, polyvinyl chloride, cellulose acetate and silicones.

The steps which may be involved in the manufacture of typical fabrics in accordance with this invention, will now be described in more detail for the purpose of facilitating the attainment of a more comprehensive appreciation of the invention.

FIGURE 1 is a diagrammatic view sequentially illustrating a simplified embodiment of a method of making a fabric according to this invention;

FIGURE 2 is a diagrammatic cross-sectional view of the layered assembly of FIGURE 1 prior to needling;

FIGURE 3 is a diagrammatic cross-sectional view of the composite needled structure of FIGURE 1;

FIGURE 4 is a diagrammatic cross-sectional View of the composite needled structure of FIGURE 1 after fibres therein have been crimped.

A sandwich structure which consists of a foamed plastic material interposed between two fibrous layers, is constructed in the following manner. One fibrous layer 10, itself comprising a plurality of superimposed fibrous webs, is withdrawn from a supply roll 12 and deposited on an endless continuously moving conveyor belt 14. The foamed plastic material 16 is then unwound from a supply roll 18 and deposited as a sheet on the previously deposited fibrous layer 10. A second fibrous layer 20, again formed of a plurality of superimposed fibrous webs, is withdrawn from a supply roll 22 and deposited on the foamed plastic sheet 16 The resulting sandwich structure is then fed through a single bed needle loom 24 of conventional design which comprises a horizontal surface 26 and a needle board 28 arranged to reciprocate in the vertical plane and provided with the usual barb needles 30 which pass in and out of the sandwich structure. In the course of their movement into the sandwich structure, the needles pass initially through the top fibrous layer 20, some of the fibres of which are engaged by the barbs, after which the needles 30 penetrate the foamed plastic sheet 16 and pass into the bottom fibrous layer 10.

The fibres carried by the barbs of the needles may merely extend into the bottom fibrous web 10 or they can pass entirely across it and protrude a variable distance beyond its outer surface as fibre tufts 32, as shown in FIGURE 3. The disposition of the needled fibres in this way is determined by the depth of needling which may readily be adjusted in a known manner. When the needled fibres protrude beyond the outer surface of the fibrous layer as fibre tufts 32, they may, provided there is a sufficient density thereof, this being directly related to the penetration density i.e. number of needle punches per unit area, form a pilous surface. The density of fibre tufts may be such that the pilous surface obscures from view the underlying fibrous layer 10. When the web 10 contains potentially crimpable fibres, and the needled structure is subjected to a treatment which develops the crimp, the fibre tufts 32 crimp into mushroom-shaped protuberances 34 (FIG- URE 4) which press against the outer face of the web 10.

The needled fibres which pass from one fibrous layer through the foamed plastic sheet and at least into the opposite fibrous layer, serve to key both of the fibrous layers to the central foamed plastic sheet. This keying action may be augmented and the tensile strength, dimensional stability and resistance to delamination of the fabric correspondingly enhanced by subjecting the sandwich to a further needling operation in the opposite direction, relative to the arrangement of the layers to the first needling operation. This may be achieved by everting the needled fabric, for instance, by passage around a series of rollers, and then taking it through the same, or another, but similar, needle loom. In this needling operation, the needles encounter initially the fibrous layer which, during the first needle-punching operation was on the bottom of the sandwich, and, consequently, fibres are carried by the needles, from the top fibrous layer through the foamed plastic sheet and into or through, depending on the depth of needling, the opposite fibrous layer which is now the bottom layer of the structure. Instead of effecting the two needle punching operations as separate stages in the manufacturing process, they can be accomplished in one stage by passing the sandwich through a doublebed needle loom.

The needle-punched fabric comprises the foamed plastic sheet sandwiched between, and secured to, the two fibrous layers. Each of the fibrous layers contain some fibres which have been reoriented by the needle-punching operation into planes normal to the outer surface of the layer and which extend through perforations, made by the needles, in the foamed plastic sheet, into and, where desired, through the opposite fibrous layer. The reoriented fibres secure the foamed plastic sheet to the two fibrous layers and impart integrity and cohesion to the fabric. In those instances where the reoriented fibres protrude beyond the outer fibrous layers, the fabric is a laminated construction with five strata arranged in the following Sequence:

(i) a fibre tuft stratum (ii) a fibrous layer which contains vertically disposed fibres, and fibres arranged in the plane of the layer (iii) the foamed plastic sheet which constitutes a distinct stratum within the fabric and which contains perforations (occupied by vertically disposed fibres) made by the needles (iv) a fibrous layer which like layer (ii) contains vertically disposed fibres and fibres arranged in the plane of the layer (v) a fibre tuft stratum.

At appropriate penetration densities the fibre tuft strata substantially obscure the underlying fibrous layers and they provide the fabric with pilous surfaces of a similar appearance. Hence, the fabric is of a reversible nature and its utility in certain applications correspondingly enhanced.

When the fibrous layers, or one of them, contain retractable fibres, the coherency and integrity of the needled fabric and consequently the tensile strength, dimensional stability and resistance to delamination may be improved by subjecting the fabric to a treatment to retract those fibres. Most conveniently, the fibres are retracted by heating the needled fabric. The actual temperature employed depends upon the nature of the fibres and the foamed plastic sheet for it is essential that the plastic sheet be substantially unaffected by the heat treatment. Instead of heat, the treatment may involve the exposure of the needled fabric to the action of a swelling agent for the retractable fibres, or to a combination of heat and a swelling agent.

The swelling agent can be applied to the needled fabric in a number of different ways, for instance, the fabric can be carried through a vessel containing the swelling agent, or the swelling agent can be sprayed, or alternatively it can be poured in a stream or drops thereon. The swelling agent need not necessarily be a liquid and, in those instances in which a solid is employed it is necessary to apply it in a suitably fluidised form, for example, as a solution or dispersion in a liquid vehicle. The treatment with a swelling agent may be combined with a simultaneous or consecutive heat treatment. In those circumstances in which the needled fabric is modified in the interests of favourably developing its tensile strength, dimensional stability and resistance to delamination, by bonding together fibres therein, it is necessary to subject the needled fabric in which the fibres may or may not be retracted to a treatment to bond fibres therein.

The bonding treatment may, for example, involve impregnating the fibrous layer or layers with a natural or synthetic resin, or by incorporating therein thermoplastic material, in powder or fibre form, having a softening point low-er than that of the fibres, or the other fibres, present in the layer or layers, and then applying heat, and frequently pressure also, to the fabric.

When the fibrous layers, or one of them, contain composite fibres with a potentially adhesive component, the bonding together of fibres as a result of inter-fibre adhesion, is readily effected through the activation of the potentially adhesive component. Conveniently, the activation of the potentially adhesive component is accomplished in the same treatment as that used to retract, by crimping, the composite fibres.

The needled fabric because of its unique construction possesses a number of advantageous properties. Thus, the presence therein of the two fibrous outer layers imparts the general appearance of a fabric derived from the needling of a fibrous structure. Quite apart from their contribution to the aesthetic appeal of the fabric, the fibrous outer layers give it a soft and warm handle and consequently, the fabrics are particularly well suited for the making of garments which are comfortable to wear. The presence in the fabrics of the layer of the foam material enhances their insulating (both to heat and cold) properties and their air permeability. Furthermore, the foam material as an integral part of the novel fabric increases the elasticity thereof and its ability to stretch, which are important considerations in relation to its use in the making of certain articles of apparel.

The fabrics of this invention have a diversity of applications ranging from the making of upholstery and other covering materials to their use in the making of article of apparel. They are particularly well suited to the making of garments such as ski trousers, and cold-weather apparel, for instance, wind-cheaters and anaraks, of all kinds.

The following examples are intended to illustrate but not to limit the invention.

Example I A layered structure was constructed from the following layers superimposed one on the other.

Top layer.-A fibrous Web having a weight of '8 ounces per square yard and made by carding, using a cotton card, a quantity of 6 denier, two and a half inch poly(hexamethylene adipamide) staple fibres.

Central layer.-A sheet of a polystyrene foam material having a weight of approximately 3 ounces per square yard.

Bottom layer.--A fibrous web of a similar composition and weight as the fibrous web of the top layer.

This sandwich structure was passed between the nip of two pressure rollers and then taken through a needle loom twice, the structure being everted between passes through the loom. In the loom, the structure was needled with regular 32 gauge barbed needles as supplied by the Textile Machine Works, Leicester as type N5/2350/1 and the loom was adjusted so as to give a penetration density of 300 needle punches per square inch, and a depth of needling of one inch whereby the first few barbs of each needle penetrated beyond the outer surface of the bottom fibrous layer with the first barb extending about inch beyond it.

As a result of the needling, a proportion of the fibres in the two outer layers were punched through the polystyrene sheet and the opposite fibrous layer, beyond the outer surface of which they protruded as fibre tufts. The presence of these tufts on the surfaces of the fabric imparted thereto the appearance of a conventional pile surfaced fabric.

Example H A layered structure was built up from the following layers superimposed one on another.

Top layer.-A fibrous web having a weight of 6 ounces per square yard, was made by carding, using a cotton card, and cross-lapping a quantity of 12 denier, two inch staple fibres formed from composite fibres consisting of equal proportions by Weight of poly(hexamethylene adipamide) as one component and an 80/20 random copolymer of poly (hexamethylene adipamide) and poly (epsilon carprolactam) as the other, the two components being arranged in a side-by-side relationship.

Central layer.A sheet of a polyester based polyurethane foam material having a weight of approximately 2 ounces per square yard.

Base layer.A fibrous web of similar composition and weight to the web of the top layer.

This sandwich structure was passed between the nip of two pressure rollers and then taken through a needle loom twice, the structure being turned over between passes through the loom. In the needle loom, the structure was needled with regular 32 gauge barbed needles as supplied by Textile Machine Works, Leicester as type N/2350/1 and the loom was set so as to give 300 needles penetrations per square inch of surface, and a depth of needling of half an inch.

As a result of the needling, a proportion of the composite fibres in the two outer layers were re-oriented in a plane normal or substantially so to the planar surface of each of those outer layers, and in that position extended in the thickness direction of the fabric from one outer layer through the foamed plastic sheet and the opposite outer layer, beyond the planar surface of which they projected as fibre tufts. The presence of these tufts which virtually obscured the underlying fibrous layer from view gave the fabric the appearance of a tufted pile fabric.

The needled fabric was then heated in an air oven at a temperature of 230 C. for a period of 3 minutes. The heat treatment had a dual effect. In the first place it caused composite fibres to crimp. Such crimping was accompanied by an overall reduction of 15 percent in the area of the needled fabric and a crimping of the tufts of the needled fibres so as to form mushroom-shaped protuberances which pressed against the planar surface thereby enhancing the dimensional stability and resistance to delamination of the fabric to the needling action. These properties were developed to an even greater extent in in the second effect of the heat treatment, which was to bond composite fibres one to another, thereby securing the needled and crimped fibres in position, through activation of the potentially adhesive component i.e. the copolymer component of the composite fibre.

The resulting fabric was found to possess a greater flexibility and resilience, and in addition, superior insulating properties and air permeability than a fabric derived from a structure consisting of the fibrous layer sandwiched between two fibrous layers, and yet it had a well developed textile-like handle, and an adequate dimensional integrity, tensile strength and resistance to delamination.

What I claim is:

1. A fabric comprising a layer of flexible foam material sandwiched between two fibrous layers, a proportion of the fibres from at least one fibrous layer extending in the thickness direction of the fabric from that layer through the flexible foam material and into and through the other fibrous layer such that these fibres project beyond the outer face of that fibrous layer and are crimped so as to form mushroom-shaped protuberances which press against said outer face.

2. A fabric as claimed in claim 1 in which the crimped fibres are composite fibres.

'3. A fabric as in claim 1 wherein said crimped fibres are composite fibres possessing potential crimp, said fibers containing at least two fibre-forming polymeric components arranged in adherent relationship along the length of the respective fibre, one of said components being potentially adhesive and located in the fibre so as to form at least a portion of its peripheral surface.

4. A fabric as claimed in claim 2 in which the composite fibres contain a potentially adhesive component.

5. A fabric as claimed in claim 4 wherein the composite fibres are bonded to contiguous fibres by means 3; the potentially adhesive component of the composite res.

6. A process for manufacturing a fabric which comprises interposing a layer of flexible foam material between two fibrous layers at least one of which layers contains at least a proportion of fibres possessing a potential crimp, needle punching the assembly from at least one side thereof so that fibres from at least one of the layers extend in the thickness direction of the fabric from that layer through the flexible foam material and into and through the other fibrous layer so that they project beyond the outer face of that fibrous layer and subjecting the needle punched assembly to a treatment to cause said potential crimpable fibres to crimp into mushroomshaped protuberances which press against said outer face.

7. A process as claimed in claim 6 in which at least one of the fibrous layers is formed from at least a proportion of composite fibres possessing potential crimp.

8. A process as in claim 6 wherein said crimped fibres are composite fibres possessing potential crimp, said fibres containing at least two fibre-forming polymeric components arranged in adherent relationship "along the length of the respective fibre, one of said components being potentially adhesive and located in the fibre so as to form at least a portion of its peripheral surface.

9. A process as claimed in claim 7 in which at least one of the fibrous layers is formed from at least a proportion of composite fibres possessing potential crimp and having a potentially adhesive component.

10. A process as claimed in claim 9 in which a needle punched assembly is subjected to a treatment to render adhesive the potentially adhesive component.

References Cited UNITED STATES PATENTS 3,347,736 10/ 1967 Sissons 161-67 ROBERT F. BURNETT, Primary Examiner ROGER H. CRISS, Assistant Examiner US. Cl. X.R. 

